The invention relates to a rotary opener and closer for screws, screw closures on bottles, jars and the like with two converging side walls (2a, 2b) which, in the use position, project vertically downwards from the rotary plane and which are interconnected at the ends at which they have their maximum spacing by an approximately semicircular side wall (2c), a rough surface for engagement on the edge of the workpiece (closure) being provided on the side wall or side walls.
U.S. Pat. No. 3,760,657 discloses a rotary opener, whose side walls converge in such a way that rotary closures or caps with different diameters can be opened. The rough surface is formed by teeth on one of the converging side walls. The facing converging side wall and the semicircular side wall are smooth, so that the force which is expended by the operator on turning the closure is transferred to a relatively small area on the edge of the closure to be opened. This can lead to an undesired deformation and damage to the closure.